1. Field of the Invention
The present invention relates to a gas heat pump-type air conditioner in which a compressor is driven using a gas engine as a drive source, and in particular, a gas heat pump-type air conditioner that can reliably notify the user about the time for changing the engine oil.
2. Description of the Related Art
An air conditioner that carries out cooling and heating by using a heat pump comprises a cooling circuit that includes elements such as an interior heat exchanger, a compressor, an exterior heat exchanger, and an expansion valve. The interior cooling and heating is realized by carrying out the respective exchange of air and heat in an interior heat exchanger and an exterior heat exchanger while the refrigerant is circulating through this circuit. In addition, in this cooling circuit, a refrigerant heater is provided for directly heating the refrigerant itself so as not to depend only on the heat of the refrigerant being absorbed (during operation as a heater) by the exterior heat exchanger.
However, in recent years, instead of the electric motor that is normally used as the drive source of the compressor in the cooling circuit described above, compressors that use gasoline engines as a drive source are being developed. Air conditioners that use this gas engine are generally called gas heat pump-type air conditioners (hereinbelow, abbreviated xe2x80x9cGHPxe2x80x9d). Like the air conditioner provided with a compressor that uses an electrical motor (hereinbelow, abbreviated xe2x80x9cEHPxe2x80x9d), with the GHP relatively inexpensive gas is used as the fuel and the running cost does not become expensive, and thus they make possible cost reductions for the users.
In addition, in a GHP, during the heating operation, for example, if the exhaust heat of the high temperature exhaust gas discharged from the gas engine is used as the heat source for the refrigerant, it is possible to obtain a superior heating effect, and at the same time, the efficiency of the energy use can be increased. Incidentally, the heating capacity in a low atmospheric temperature becomes 1.2 to 1.5 times higher than the EHP. In addition, if this type of apparatus is introduced, mechanisms such as the refrigerant heater described above need not be specially provided in the refrigerant circuit.
In addition, in a GHP, the frost removal operation, that is, the defrosting operation, of the interior heat exchanger that is necessary during heating operation can also be implemented by using the waste heat of the engine. Generally, the defrosting operation in the EHP is performed by carrying out frost elimination from the exterior heat exchanger by stopping the heating operation and temporarily carrying out a cooling operation. In this case, the pleasantness of the interior environment deteriorates because cool air is blown into the interior, and this is not desirable in terms of the air conditioning sensation. In a GHP, a continuous heating operation is possible by using the wasted heat due to the circumstances described above, and the problems that cause concern in an EHP do not occur.
However, although GHP has these many advantages, the following problems can be pointed out about the conventional GHP.
As described above, in a GHP engine oil that lubricates the gas engine is used because a gas engine serves as the drive source for the compressor. Since this engine oil will deteriorate while the gas engine is operated, at an appropriate time (that is, before the deterioration begins) maintenance in which an oil change is carried out is necessary. However, the cumulative hours of operation of the gas engine at which the change of the engine oil becomes necessary is rather long, for example, about 10,000 hours, and thus correctly judging the appropriate time for the oil change is difficult.
Against this background, a control method is proposed in Japanese Patent No. 3066123, wherein, when the cumulative hours of operation of the engine reaches a predetermined number of hours, the engine automatically stops, and at the same time, a selection choice is provided that allows extended operation of the engine for a predetermined amount of time even if an oil change is not carried out. Alternatively, when the cumulative hours of operation of the engine has reached a predetermined number of hours, an oil change warning light is displayed, and after the warning signal display for the oil change is displayed, the engine automatically stops at a predetermined operating time if an oil change is not carried out, and at the same time a selection choice is provided that allows extended operation of the engine for a predetermined time.
However, this conventional technology always stops the operation of the engine once at a predetermined amount of cumulative hours of operation of the engine or after the passage of a predetermined extended operation time without an oil change. Thereby, either the oil change is completed before the predetermined amount of the cumulative hours of operation has been reached, or the operation of the compressor that circulates the refrigerant becomes impossible when the oil change is not completed quickly after the oil change warning signal is displayed, and thus there are cases wherein the forcible stopping of the air conditioning operation becomes unavoidable when the time for the oil change has arrived.
This type of forcible stopping of the air conditioning operation is undesirable in terms of the capacity of a gas heat pump-type air conditioner to maintain a pleasant interior environment by the cooling operation and the heating operation, for example. Therefore, the development of a heat pump air conditioner that does not forcibly stop the operation of the air conditioner, and furthermore can reliably notify the user about the arrival of the time for an oil change for the gas engine is desirable.
In consideration of the problems described above, it is an object of the present invention to provide a gas heat pump-type air conditioner that can reliably notify the user about the arrival of the time for changing the engine oil of the gas engine that drives the compressor without stopping the operation of the gas engine.
The present invention uses the following device to resolve the problems described above.
In a first aspect of a gas heat pump-type air conditioner that forms a cooling cycle by circulating refrigerant using a compressor having a gas engine as a power source, the user is notified about the time for changing the engine oil by displaying a warning while continuing to operate the gas engine when the cumulative hours of operation (t) of the gas engine has reached a predetermined time (T2), and at the same time displaying a warning and carrying out a warning restoration operation procedure after carrying out the first stop procedure subsequent to reaching the predetermined time (T2).
According to this type of a gas heat pump-type air conditioner, while the operation of the gas engine continues, at the point in time that the cumulative hours of operation (t) reaches a predetermined time (T2), the user is notified that the time for changing the engine oil has arrived by a warning message, and at the same time, after the initial operation stop subsequent to reaching the predetermined time (T2), by carrying out a warning restoration operation procedure that is different from the normal procedure, the user becomes strongly aware of the time for changing the engine oil.
In a second aspect of the gas heat pump-type air conditioner that forms a cooling cycle by circulating refrigerant with a compressor having a gas engine as a power source, the user is notified about the time for changing the engine oil by forcibly reducing the engine revolutions for the gas engine to the minimum number of revolutions when the cumulative hours of operation (t) of the gas engine has reached a predetermined time (T3).
According to this type of a gas heat pump-type air conditioner, when the cumulative hours of operation has reached a predetermined time (T3), the gas engine is operated after forcibly reducing the number of revolutions to the minimum, and thus a state in which the capacity of the air conditioner is drastically reduced occurs, and the user can be notified about the time for changing the engine oil while continuing the operation of the gas engine. Furthermore, by operating the gas engine forcibly at the minimum number of revolutions, the damage risk to the gas engine due to deterioration of the engine oil can be reduced to a minimum.
In this type of gas heat pump-type air conditioner, after the initial stop procedure subsequent to reaching the predetermined time (T3), preferably a warning is displayed and a warning restoration operation procedure is carried out. Thereby, after the initial operation stop subsequent to reaching the predetermined time (T3), by carrying out a warning restoration operation procedure that differs from a normal procedure, the user can be strongly made aware again that the time for changing the engine oil has arrived.
In a fourth aspect of the gas heat pump-type air conditioner that forms a cooling cycle by circulating refrigerant with a compressor having a gas engine as a power source, when the cumulative hours of operation (t) of the gas engine has reached a predetermined time (T4) and each time the cumulative hours of operation (t) is increased from the predetermined time (T4) by a predetermined time (xcex94t), the user is notified about the time for changing the engine oil by forcibly reducing the engine revolutions of the gas engine to the minimum number of revolutions, and at the same time after the predetermined time (T4) has been passed, when the stop procedure is carried out, a warning is displayed and at the same time a warning restoration operation procedure is carried out.
According to this type of a gas heat pump-type air conditioner, when the cumulative hours of operation of the gas engine has reached a predetermined time (T4) and each time the cumulative hours of operation (t) has increased by a predetermined time (xcex94t) from the predetermined time (T4), the gas engine is operated by forcibly reducing the number of revolutions to the minimum number, and thus a state in which the air conditioner capacity is drastically reduced occurs, and the user can be notified a plurality of times that the time for changing the engine oil has arrived while the operation of the gas engine continues. In addition, after carrying out the stop procedure subsequent to reaching the predetermined time (T4), a warning is displayed and at the same time the warning restoration operation procedure is carried out, and thus after the operation stop subsequent to reaching the predetermined time (T4), a warning restoration operation procedure is carried out that is different from the normal procedure, and thus the user can be made strongly aware again over a plurality of times that the time for changing the engine oil has arrived.
In addition, in this type of gas heat pump-type air conditioner, when the cumulative hours of operation (t) becomes a predetermined time that is the predetermined time (xcex94t) added to the predetermined time (T4), preferably the operation of the gas engine is forcibly stopped, and thereby because the cumulative hours of operation (t) of the gas engine is limited, damage originating in inadequate lubrication can be prevented.
In a sixth aspect of the gas heat pump-type air conditioner that forms a cooling cycle by circulating refrigerant with a compressor having a gas engine as a power source, the gas heat pump-type air conditioner comprises: a first warning stage in which, when the cumulative hours of operation (t) of the gas engine has reached a first predetermined time (T1), the user is notified about the time for changing the engine oil by displaying a warning while continuing to operation the gas engine; a second warning stage in which, when the cumulative hours of operation (t) has reached a second predetermined time (T2), the user is notified about the time for changing the engine oil by displaying a warning while continuing to operation the gas engine when the cumulative hours of operation (t) of the gas engine has reached a second predetermined time (T2) and at the same time, after the first stop procedure is carried out subsequent to having reached the second predetermined time (T2), in addition to displaying a warning the warning restoration operation procedure is carried out; a third warning stage in which, when the cumulative hours of operation (t) has reached a third predetermined time (T3), the user is notified about the time for changing the engine oil by forcibly reducing the engine revolutions of the gas engine to the minimum number of revolutions, and after the first stop procedure carried out subsequent to having reached the third predetermined time (T3), a warning is displayed and at the same time the warning restoration operation procedure is carried out; a fourth warning stage in which, when the cumulative hours of operation (t) of the gas engine has reached a fourth predetermined time (T4) and each time the cumulative hours of operation (t) is increased from the predetermined time (T4) by a predetermined time (xcex94t), the user is notified about the time for changing the engine oil by forcibly reducing the engine revolutions of the gas engine to the minimum number of revolutions and at the same time after the fourth predetermined time (T4) has been passed when the stop procedure is carried out, a warning is displayed and at the same time a warning restoration operation procedure is carried out; and a fifth warning stage in which, when the cumulative operation value (t) has become a predetermined time (T5), which is a predetermined time (xcex94t) or greater added to the predetermined time (T4), the operation of the gas engine is forcibly stopped.
According to this type of gas heat pump-type air conditioner, from the time that the cumulative hours of operation (t) of the gas engine has reached a first predetermined time (T1) until reaching the fifth predetermined time (T5), the user can be reliably notified about the arrival of the time for changing the oil by repeating many times the first through fourth warning stages without stopping the gas engine.
In the gas heat pump-type air conditioner according to any of the first, third, fourth, fifth, or sixth aspects, preferably in the operation start procedure up to a predetermined number of times, the warning restoration operation procedure displays a warning while continuing the operation stop state and at the point in time that the operation start procedure is carried out more than the predetermined number of times displays a warning and starts the operation, and thereby the user can be made strongly aware that the time for changing the engine oil has arrived by not allowing the smooth operation start that occurs during normal times and displaying a warning.